Pressure regulating valve

A pressure regulating valve, comprising:

• a case that includes a primary chamber and a secondary chamber;
• a valve moving member that includes a piston and a valve element, wherein:
• the valve moving member moves in such a manner as to cause communication or block communication between the primary chamber and the secondary chamber within the case, and
• one end of the piston faces the secondary chamber and the other end faces a reference pressure chamber;
• a plurality of seal members arranged between said case and said valve moving member, wherein:
• said plurality of seal members are made of different materials, and
• said plurality of seal members are arranged between a side surface of said piston and an inner wall case;
• and
• communicating means for causing a space and said reference pressure chamber to communicate, wherein:
• the space is defined by said side surface of said piston, said inner wall of said case and said plurality of seal members,
• the communicating means is formed in a body of the case, and
• the communicating means is configured to connect the space and the reference pressure chamber such that a pressure of the space is regulated when the piston moves,
• wherein the communicating means is formed at an inner wall surface of the body of the case at a location of a first seal member of the plurality of seal members on a side of said reference pressure chamber, and the communicating means is formed by undulations so that gas can communicate between the s ace and the reference pressure chamber.